Flexible Integration Research Articles

E-LION: Data integration semantic model to enhance predictive analytics in e-Learning

In the last years, Learning Management systems (LMSs) are acquiring great importance in online education, since they offer flexible integration platforms for organising a vast amount of learning resources, as well as for establishing effective communication channels between teachers and learners, at any direction. These online platforms are then attracting an increasing number of users that continuously access, download/upload resources and interact each other during their teaching/learning processes, which is even accelerating by the breakout of COVID-19. In this context, academic institutions are generating large volumes of learning-related data that can be analysed for supporting teachers in lesson, course or faculty degree planning, as well as administrations in university strategic level. However, managing such amount of data, usually coming from multiple heterogeneous sources and with attributes sometimes reflecting semantic inconsistencies, constitutes an emerging challenge, so they require common definition and integration schemes to easily fuse them, with the aim of efficiently feeding machine learning models. In this regard, semantic web technologies arise as a useful framework for the semantic integration of multi-source e-learning data, allowing the consolidation, linkage and advanced querying in a systematic way. With this motivation, the e-LION (e-Learning Integration ONtology) semantic model is proposed for the first time in this work to operate as data consolidation approach of different e-learning knowledge-bases, hence leading to enrich on-top analysis. For demonstration purposes, the proposed ontological model is populated with real-world private and public data sources from different LMSs referring university courses of the Software Engineering degree of the University of Malaga (Spain) and the Open University Learning. In this regard, a set of four case studies are worked for validation, which comprise advance semantic querying of data for feeding predictive modelling and time-series forecasting of students’ interactions according to their final grades, as well as the generation of SWRL reasoning rules for student’s behaviour classification. The results are promising and lead to the possible use of e-LION as ontological mediator scheme for the integration of new future semantic models in the domain of e-learning.

How regulating and cultural services of ecosystems have changed over time in Italy

In this experimental study, different components are computed for three different ecosystem services (ES). Specifically, supply, demand and use are estimated for pollination service, flood risk regulation service and nature-based tourism. These are analysed and assessed in 2012 and 2018 for the Italian context, in order to estimate the evolution over this period and to allow a significant comparison of results. The same methodology and models are applied for the selected accounting years and accounting tables and tend to reflect as closely as possible the System of Environmental-Economic Accounting-Ecosystem Accounting (SEEA EA), which is the international standard endorsed by the United Nations to compile Natural Capital Accounting in 2021. Both biophysical and monetary assessments are performed using the ARIES technology, an integrated modelling platform providing automatic and flexible integration of data and models, via its semantic modelling nature. Models have been run adjusting the components of the global modelling approach to the Italian context and, whenever available, prioritising the use of local data to carry out the study. This approach is particularly useful to analyse trends over time, as potentially biased components of models and data are substantially mitigated when the same biases is constant over time. This study finds an increase in benefits over the period analysed for the ES examined. The main contribution of this pioneering work is to support the idea that ES accounting or Natural Capital Accounting can provide a very useful tool to improve economic and environmental information at national and regional level. This can support processes to provide the necessary incentives to steer policy-making towards preventative rather than corrective actions, which are usually much less effective and more costly, both at environmental and economic levels. Nevertheless, particular attention must be paid to the meaning of the estimates and the drivers of these values to derive a direct or indirect relationship between the benefits observable and the actual Italian ecosystems condition.

CoFe2O4 functionalized PVDF membrane for synchronous oil/water separation and peroxomonosulfate activation toward aromatic pollutants degradation

Effective synchronous removal of water-immiscible oils and water-miscible refractory aromatic pollutants from wastewater is of great significance for water remediation. In this work, a low-cost and easy-prepared composite membrane was fabricated by vacuum assisted assembling of CoFe2O4 and tannic acid on polyvinylidene fluoride (PVDF) substrate. The CoFe2O4 functionalized PVDF membrane (CoFe2O4@PVDF) exhibited in-air superamphiphilic and underwater superoleophobic surface wettability. The resultant membrane displayed relatively favorable permeation flux (811.5 to 1837.5 Lm−2h−1) and high separation efficiency (above 99 %) in the separation of a series of emulsified oils ranged from nanoscale to microscale from water. Meanwhile, the as-fabricated CoFe2O4@PVDF membrane coupled with peroxymonosulfate (PMS) exhibited an extensive oxidizing capacity and high degradation efficiency towards aromatic contaminants with desired mineralization ability. More importantly, considering that the fabricated CoFe2O4@PVDF membrane possessed special super-wettability as well as PMS activation-based catalytic ability, it also applied in the treatment of simulated complex wastewater. The process achieved effectively synchronous oil/water separation and PMS activation toward pollutants degradation. Besides, in five cyclic continuous “degradation-separation” tests, the recovered CoFe2O4@PVDF membrane after PMS-based degradation in each cycle could separate oil/water emulsions as usual. It exhibited almost complete oil rejection and flux recovery property under multicycle filtration, demonstrating its excellent durability and stability. This flexible integration of PMS-based AOP catalytic capability and super-wettability into a composite membrane can provide inspiration for effective complicated wastewater rehabilitation.

Interventions to identify and manage depression delivered by 'nontraditional' providers to community-dwelling older adults: A realist review.

Mental health problems experienced by older adults (60+ years of age) may remain hidden due to individual and system-level barriers. Opportunities to support early identification and management are therefore crucial. The National Health Servicerecommends wider public services that are embedded within local communities, but are not traditionally part of the healthcare landscape (i.e.,'nontraditional'),could facilitate engagement with healthcare by members of the public. Evidence for interventions involving Fire and Rescue, Police, Library services and postal workers, as nontraditional providers of mental health services, has not been synthesized previously. This review aims to understand how, why and in what contexts mental health interventions delivered by these nontraditional providers, to older adults, work. A realist review of interventions to identify and/or manage mental health problems (depression with or withoutanxiety) experienced by older adults. Systematic, cluster and iterative literature searches were conducted. Intervention evidence was appraised for rigour and explanatory relevance and then coded to inform context-mechanism-outcome configurations (CMOCs). A public advisory group supported our initial evidence search strategy and definition of key terms. This review is registered with PROSPERO (CRD42020212498). Systematic searches revealed a dearth of evidence reporting mental health interventions delivered by nontraditional providers. Our scope was adjusted to consider interventions delivered by Fire and Police services only and for wider health and wellbeing concerns (e.g., dementia, falls prevention, mental health crises). Forty-three pieces of evidence were synthesized. Key themes included: legitimizing expanded roles, focusing on risk, intervention flexibility and organization integration; further subthemes are described. Themes map onto CMOCs and inform a preliminary programme theory. Findings were transposed to mental health contexts. Findings highlight challenges and opportunities for Fire and Police services, as nontraditional providers, to deliver interventions that identify and/or manage mental health problems among older adults. Our programme theory explains what could work, how, for whom and also by whom (i.e., which public services). Further empirical evidence is needed to test interventions, understand acceptability and inform implementation. A public advisory group comprising older adults with lived experience of mental health problemsand informal caregiverscontributed to the original application, reviewed the scopeand informed the approach to dissemination.

Micro-tabless-pouch-cell (MTPC) with high energy density and exposed functional current collector for flexible device

Power sources with stable electrochemical performance, flexible integration, and function extensibility are essential to meet the demands for emerging flexible electronics. The simultaneous realization of these properties is challenging based on current solutions for designing flexible batteries. Herein, we develop a new type of design strategy called Micro-tabless-pouch-cell (MTPC), which realizes the miniaturization of pouch cells by replacing the conventional ultrasonic welding protocol with an innovative tab-glue-hot-welding process during sealing. The electrochemical performance of the electrodes in the MTPC is comparable to that of the coin cell, while the weight of the entire MTPC device is reduced by 95%, resulting in a 2230.93% increase in gravimetric energy density (14.242 Wh/kg vs 0.611 Wh/kg). The miniaturization enables the MTPC to be easily integrated on flexible substrates. Moreover, the MTPC has a unique structure of exposed current collector, which enables function extensibility. As a proof of concept, an MTPC with smart self-protection capability upon over-heating is demonstrated by integrating a reversible thermal switch composed of an Ecoflex/ethanol composite. The simultaneous realization of robust electrochemical performance, capability for flexible integration, and function extensibility in MTPC is expected to push the developments for various high-end flexible electronics that require stable input of energy.

A unified image fusion framework with flexible bilevel paradigm integration

A unified image fusion framework with flexible bilevel paradigm integration

High-adhesion PDMS/Ag conductive composites for flexible hybrid integration

The integration of silicon chips and other rigid components on soft polymeric substrate represents a viable option towards mass production of high-performance stretchable electronics, where bonding materials with high stretchability, high conductivity, and high adhesion strength become the key in the process. Polydimethylsiloxane/silver composites (PDMS/Ag) are promising candidates, but the adhesion of PDMS-based composites is usually too weak to be useful. Herein, we report a “netting and anchoring” strategy, in which a small amount of polyborosiloxane (PBS) prepolymer is added and the formed PBS networks not only net the PDMS networks with dense physical entanglements but also anchor PDMS networks to adherent surfaces with reversible bonds. The obtained composites have an adhesion strength of 2.87 MPa (8.2 times and 3.2 times higher than that of the untreated and conventional silane-treated composites) and maintain a high conductivity of 1.3 × 10−4 Ω·cm. The enhanced bonding originates from three aspects: good wettability, uniform interfacial bonding, and stress transfer from the interface to the bulk to elicit bulk energy dissipation. As an example, a stretchable temperature sensor system integrated with this strategy can resist up to 70% stretching, bending, and twisting.

Dynamics and potential significance of spontaneous activity in the habenula.

The habenula is an evolutionarily conserved structure of the vertebrate brain that is essential for behavioral flexibility and mood control. It is spontaneously active and is able to access diverse states when the animal is exposed to sensory stimuli. Here we investigate the dynamics of habenula spontaneous activity, to gain insight into how sensitivity is optimized. Two-photon calcium imaging was performed in resting zebrafish larvae at single-cell resolution. An analysis of avalanches of inferred spikes suggests that the habenula is subcritical. Activity had low covariance and a small mean, arguing against dynamic criticality. A multiple regression estimator of autocorrelation time suggests that the habenula is neither fully asynchronous nor perfectly critical, but is reverberating. This pattern of dynamics may enable integration of information and high flexibility in the tuning of network properties, thus providing a potential mechanism for the optimal responses to a changing environment.

Recent Advances in Resistive Sensor Technology for Tactile Perception: A Review

As an important part of the development of intelligent electronic technology, resistive tactile sensors have been widely researched and applied in a variety of fields. Since force sensing plays an integral role in applications such as healthcare monitoring and human-machine interaction, superiorly performing tactile force sensors with stable high-sensitivity, wide dynamic range, flexibility, ease of integration, and fabrication are urgently anticipated to be accomplished by various advanced approaches. As a result, it is of great significance to explore key factors that affect piezoresistive behavior and internal mechanism, and then optimize performance. This review systematically summarizes global researches in this field, involving creative works in piezoresistive materials, macro and micro structural design, etc., aiming to describe the current development status and provide references for sensor design. Finally, further research frontiers and strategies are proposed for the grand challenges, including flexible large-scale integration with high-resolution, signal stability and long-term reliability.

Multiferroic Self-Assembled BaTiO3–Fe Vertically Aligned Nanocomposites on Mica Substrates toward Flexible Electronics

Integration of functional thin films with a multiferroic property on flexible substrates has piqued tremendous research interest and device potential for flexible electronics. In this work, self-assembled BaTiO3–Fe vertically aligned nanocomposite (VAN) thin films have been integrated on mica substrates using pulsed laser deposition. Different buffer layers have been explored to facilitate VAN growth. The anisotropic ferromagnetic property and room temperature ferroelectric property have been achieved in the films. The bending test up to 1000 cycles signifies the mechanical stability of the physical properties. This work paves an avenue to integrate multiferroic oxide–metal nanocomposites for future flexible device integration.

Design and analysis of flexible integration of solar aided liquid air energy storage system

Liquid air energy storage (LAES) system is a promising technology for large-scale energy storage. It is not restricted by the geographical condition and has a high energy storage density. In this paper, on the base of the baseline LAES (BLAES) system, novel solar aided LAES systems with the poly-generation of cold, heat and power are designed to improve the round-trip efficiency (RTE) of the overall system and minimize the number of additional devices. In the best integration case, the solar energy is stored by using the existing air compression heat recovery system, and the air compression heat is effectively utilized. The organic Rankine cycle (ORC) device can be integrated with both the discharging process side and the charging process side to improve the RTE. The results show that the optimized air liquefaction pressure is 160 bar and the air expansion pressure is 120 bar, and the RTE is 53.26% for the BLAES system. For new system, the RTE of the best integration case is 90.49%, 69.90% higher than that of the BLAES system. The RTE of new system with the dual-side integration of ORC is improved by 15.56% compared to that of new system with the ORC single-side integration.

Spatial-Interleaving Graphene Supercapacitor with High Area Energy Density and Mechanical Flexibility.

The booming portable electronics market has raised huge demands for the development of supercapacitors with mechanical flexibility and high power density in the finite area; however, this is still unsatisfied by the currently thickness-confined sandwich design or the in-plane interdigital configuration with limited mechanical features. Here, a spatial-interleaving supercapacitor (SI-SC) is first designed and constructed, in which the graphene microelectrodes are reversely stacked layer by layer within a three-dimensional (3D) space. Because each microelectrode matches well with four counter microelectrodes and all 3D spatial-interleaving microelectrodes have narrow interspaces that maintain the efficient ions transport in the whole device, this SI-SC has a prominent liner capacitance increase along with the device thickness. As a result, the high specific areal capacitance of 36.46 mF cm-2 and 5.34 μWh cm-2 energy density is achieved on the 100 μm thick device. Especially, the microelectrodes in each layer are interdigitated, ensuring the outstanding mechanical flexibility of SI-SC, with ∼98.7% performance retention after 104 cycles of bending tests, realizing the excellent integration of high area energy density and mechanical flexibility in the finite area. Furthermore, the SI-SC units can be easily integrated into wearable electronics to power wristwatches, light-emitting diodes (LEDs), calculators, and so on for practical applications.

Thermally Drawn CNT-Based Hybrid Nanocomposite Fiber for Electrochemical Sensing.

Nowadays, bioelectronic devices are evolving from rigid to flexible materials and substrates, among which thermally-drawn-fiber-based bioelectronics represent promising technologies thanks to their inherent flexibility and seamless integration of multi-functionalities. However, electrochemical sensing within fibers remains a poorly explored area, as it imposes new demands for material properties—both the electrochemical sensitivity and the thermomechanical compatibility with the fiber drawing process. Here, we designed and fabricated microelectrode fibers made of carbon nanotube (CNT)-based hybrid nanocomposites and further evaluated their detailed electrochemical sensing performances. Carbon-black-impregnated polyethylene (CB-CPE) was chosen as the base material, into which CNT was loaded homogeneously in a concentration range of 3.8 to 10 wt%. First, electrical impedance characterization of CNT nanocomposites showed a remarkable decrease of the resistance with the increase in CNT loading ratio, suggesting that CNTs notably increased the effective electrical current pathways inside the composites. In addition, the proof-of-principle performance of fiber-based microelectrodes was characterized for the detection of ferrocenemethanol (FcMeOH) and dopamine (DA), exhibiting an ultra-high sensitivity. Additionally, we further examined the long-term stability of such composite-based electrode in exposure to the aqueous environment, mimicking the in vivo or in vitro settings. Later, we functionalized the surface of the microelectrode fiber with ion-sensitive membranes (ISM) for the selective sensing of Na ions. The miniature fiber-based electrochemical sensor developed here holds great potential for standalone point-of-care sensing applications. In the future, taking full advantage of the thermal drawing process, the electrical, optical, chemical, and electrochemical modalities can be all integrated together within a thin strand of fiber. This single fiber can be useful for fundamental multi-mechanistic studies for biological applications and the weaved fibers can be further applied for daily health monitoring as functional textiles.

Three‐dimensional hierarchical nanostructured porous epoxidized natural rubber latex/poly(vinyl alcohol) material for oil/water separation

AbstractIn the past few decades, many interesting biomaterials with unforeseen properties have attracted considerable attention due to its unique micro‐nano structure. In this work, a bio‐inspired design was proposed to develop the epoxidized natural rubber latex (ENRL)@polyvinyl alcohol (PVA) three‐dimensional (3D) porous material. Herein, the obtained epoxidized natural rubber/polyvinyl alcohol (ENR@PVA) exhibits a “grapevine‐grape” like networks with robust PVA as “grapevine” and soft latex particles as “grape”. Owing to the synergistic effect of those hierarchical micro‐nano structures and abundant hydrophilic oxygen‐containing groups, the ENR@PVA exhibits superhydrophilic and underwater superoleophobic functionality. Accordingly, benefiting from the superwettability features, the ENR@PVA shows superior separation (oil rejections are all above 99.5%) and anti‐fouling performances. More importantly, the integration of excellent flexibility and mechanical robustness guarantees a superior mechanical stability for sustainable reusability and oil recovery in the practical applications. Therefore, the research findings might promote the development of the 3D porous material and its future application for high performance oily wastewater remediation.

Flexible and High-Precision Integration of Inserts by Combining Subtractive and Non-Planar Additive Manufacturing of Polymers

Additive manufacturing of polymers offers great potential for the production of complex structures. In particular, Fused Filament Fabrication (FFF) processes can be used to create functionally integrated components, in addition to easy handling, tool-free production and large material options. By combining a FFF system with a robot, inserts of different types can be integrated automatically during the printing process [1]. The low dimensional accuracy of FFF induces great difficulties during the insertion operation. Furthermore, with FFF, a planar layer structure leads to a stair-step effect when overprinting inserts with curved outer contours and reduces the adhesion to the insert. Further, the adhesion of FFF-filaments to the insert depends on the surface treatment of the insert [1]. A FFF system was combined with a robot [2] and has now been expanded to include a subtractive finishing unit and an inline process control based on a machine vision system, which enables the dimensional accuracy of the FFF components to be checked during the printing process. To be able to produce functionally integrated components, a flexible control architecture is being developed that enables the execution of additive and subtractive process steps. Optimal integration of inserts with complex geometries is facilitated by using non-planar layers in the FFF path planning. For this purpose, the filament layers of the FFF components follow the tilted or curved contours of the inserts. The modified process is demonstrated by manufacturing an integrated stator for an electric motor. A system for an additive-subtractive process for the integration of functional inserts was developed. In addition, a concept for the implementation of an improved connection of the inserts through non-planar FFF layers was created. First steps for the integration of the various system-modules and optical analysis of the dimensional accuracy and the development of a printing strategy for non-planar overprinting of the inserts have been realized.

Low-Carbon Robust Predictive Dispatch Strategy of Photovoltaic Microgrids in Industrial Parks

With the flexible integration of local renewable energy with the smart distribution network system, the problems of high operating costs and power shortage can be effectively solved. However, taking the industrial park microgrid with high penetration photovoltaic as an example, due to the uncertainties and fluctuations arising from the meteorological conditions and the load demands, the safe and reliable operation of the microgrid system has been threatened significantly. Operators often need to pay additional unnecessary costs to maintain stable operations of the microgrid. Therefore, in this study, a dispatch strategy based on robust model predictive control considering low-carbon cost is designed to reduce the adverse effects of uncertainties. First, a low-carbon energy management scheme is formulated based on short-term source and load forecast information in which a two-stage robust optimization solution method is used to generate the optimal dispatch scheme under the worst scenario. Then, an intraday real-time strategy with a closed-loop feedback mechanism is formed based on the model predictive control. Finally, the feasibility of the proposed strategy is simulated and analyzed based on the measured data of the photovoltaic microgrid in the industrial park. The results show that compared with the general intraday scheduling strategy and the day-ahead robust strategy, the proposed strategy can effectively get low-carbon scheduling plans considering the uncertainty of source and load while efficiently balancing the robustness and economy of the grid-connected industrial park photovoltaic microgrid system operation.

Flexible environment-tolerant electroluminescent devices based on nanocellulose-mediated transparent electrodes

Stretchable electroluminescent (EL) devices show great potential for wearable displays. However, the integration of stretchability, flexibility, temperature-tolerance, waterproofness and biocompatibility into a single EL device remains a challenge. Herein, we report a facile full solution-process method for a novel EL device consisting of a dielectric luminescent layer sandwiched between two silver nanowires-cellulose nanocrystals with II crystalline allomorphs/polydopamine-polydimethylsiloxane (CNC II-AgNWs/PDA-PDMS) electrodes. CNC II is used as a green dispersant, film-forming agent and antioxidant to improve the optical, electrical, mechanical and antioxidant properties of the electrodes. The electrodes exhibit a smooth surface, low sheet resistance (~11 Ω sq−1), high transparency (~79.2 %), ideal stretchability (~100 % strain) and excellent inoxidizability. The assembled EL devices with outstanding tensile stability and fatigue resistance demonstrate excellent luminance, flexibility and stretchability underwater and at extreme temperatures, as well as intrinsic biocompatibility. Our multifunctional EL devices with outstanding integrated properties provide new insights for the next-generation flexible electronics.

In Situ Preparation of High‐Quality Flexible Manganese‐Halide Scintillator Films for X‐Ray Imaging

AbstractEnvironmentally friendly metal halides have emerged as emitters in lighting and X‐ray imaging applications. However, the conventional scintillator fabrication process involves high‐temperature sintering or powder grinding, resulting in large bulk crystals or agglomerates, which hamper flexible device integration and processability. Here, large‐area flexible scintillation screen films containing (C24H20P)2MnBr4 nanocrystals are prepared in situ, which prevents the generation of agglomerated powders or large bulk crystals, and the preparation duration and cost are reduced. The film exhibits good mechanical stability and homogeneity, and the photoluminescence quantum yield is over 85%. Moreover, the film presents excellent scintillation performance with detection limit as low as 0.608 μGyair s−1 and 14.5 lp mm−1 X‐ray imaging resolution. This excellent performance and simple preparation method are expected to favor industrial mass production.

Complementary representations of time in the prefrontal cortex and hippocampus.

Episodic memory binds the spatial and temporal relationships between the elements of experience. The hippocampus encodes space through place cells that fire at specific spatial locations. Similarly, time cells fire sequentially at specific time points within a temporally organized experience. Recent studies in rodents, monkeys, and humans have identified time cells with discrete firing fields and cells with monotonically changing activity in supporting the temporal organization of events across multiple timescales. Using in vivo electrophysiological tetrode recordings, we simultaneously recorded neurons from the prefrontal cortex and dorsal CA1 of the hippocampus while rats performed a delayed match to sample task. During the treadmill mnemonic delay, hippocampal time cells exhibited sparser firing fields with decreasing resolution over time, consistent with previous results. In comparison, temporally modulated cells in the prefrontal cortex showed more monotonically changing firing rates, ramping up or decaying with the passage of time, and exhibited greater temporal precision for Bayesian decoding of time at long time lags. These time cells show exquisite temporal resolution both in their firing fields and inthe fine timing of spikes relative to the phase of theta oscillations. Here, we report evidence of theta phase precession in both the prefrontal cortex and hippocampus during the temporal delay, however, hippocampal cells exhibited steeper phase precession slopes and more punctate time fields. To disentangle whether time cell activity reflects elapsed time or distance traveled, we varied the treadmill running speed on each trial. While many neurons contained multiplexed representations of time and distance, both regions were more strongly influenced by time than distance. Overall, these results demonstrate the flexible integration of spatiotemporal dimensions and reveal complementary representations of time in the prefrontal cortex and hippocampus in supporting memory-guided behavior.

Dynamic optimization with flexible heat integration of a solar parabolic trough collector plant with thermal energy storage used for industrial process heat

There is an increasing need to reduce fossil fuel consumption used for industrial process heat to slow the effects of climate change. Using solar thermal heat is a viable way to replace fossil fuel use, but solar industrial process heat plants have limited implementation due to large upfront costs and inefficiencies from the inherent variability from solar energy. Having more flexible and optimized control over these plants can enable them to be more efficient. In this work, a solar industrial process heat plant with thermal energy storage that can flexibly collect and deliver heat to two industrial processes (flexible heat integration) is dynamically modeled with control setpoints found by a dynamic optimization method. The optimized case can increase the solar efficiency of the plant by 7.5% on average relative to a base case. Results show that it is best to collect heat at lower temperatures for all but ideal solar conditions, only medium to high quality heat should be stored in large quantities, and exchanging heat with a lower temperature heat sink is generally more efficient. The optimized case is able to reduce the levelized cost of heat of the plant to $31.83/MWhth compared to a base case value of $34.10/MWhth. The optimized case can reduce emissions by 22.2% compared to a plant which uses only natural gas. This work shows that dynamic optimization with flexible heat integration can be a cost-effective way to increase efficiency so that more of these types of plants can be implemented.